Re: Redefining 'Class'Output

[Tucker Taft <stt@averstar.com>]

Matt Brennan wrote:
> 
> Hiya,
>      I am trying to stream objects of various tagged types between two
> boxes.
> 
> There are different compilers at each end with differing
> Ada.Tags.External_Tags. One compiler (GNAT) has an external
> representation the same as the Ada.Tags.Expanded_Name (defined by the
> language to be all capitals) and the other compiler uses the same string
> but all lower case.

One solution is to specify the value of External_Tag for
each type.  External_Tag is a specifiable attribute.  E.g.:

    for Tagged_Type_T'External_Tag use "P.TAGGED_TYPE_T";

See RM 95 13.3(75).

> In order to guarantee compatibility at each end, i wish to redefine the
> 'Class'Output (and 'Class'Input) for my base type to use the (language
> defined) Expanded_Name in the stream rather than the external tag...
> like so:

This is definitely the hard way, and I wouldn't recommend it...

> ...
> Any assistance would be great.
> 
> Thanks,
> 
>   matt
> 
> --
> -- Matt Brennan || Vision Systems Ltd || +61 8 8300 4686
> --

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA